They promise an oasis of calm and a bit of luxury amid the chaos of a busy airport terminal – but all too often airport lounges offer an underwhelming experience and poor value for money, an investigation into the pay-for service has found.

Travel reviewers from consumer watchdog Which? inspected 20 pay-as-you-go airport lounges in the UK and found that many do not offer more than a glass of cheap wine and a sad handful of stale crisps, with the average score a just about adequate 2.4 out of five.

Edinburgh’s two private airport lounges – the only Scottish ones in the survey – both scored below average at two out of five. Neither Edinburgh lounge, run by national groups Aspire and No 1, has toilets or showers or a designated quiet area, but charge £24 and £33 respectively as an entry fee on the door. The advance prices drop slightly to £21 and £26.

The Aspire Edinburgh lounge, however, does explicitly ban customers from wearing onesies – alongside other lounges owned by the same company and a range of other airports’ lounge providers.

The Which? review said: “Both Edinburgh options also failed to impress. While the Aspire lounge edged ahead for its cheaper price, inspectors found the foyer ‘dingy’, food ‘bland’ and added that passengers should only visit if they had secured a very good discount.”

Heathrow’s No 1 T3 lounge ranked the best of all of those inspected, earning four out of five.

Inspectors praised the cinema, complimentary a la carte menu and l’Occitane toiletries available in the “spotlessly clean” bathrooms.

Rory Boland, editor of Which? Travel, said: “A pay-as-you-go lounge to start your holiday early might seem like a great option if you are willing to fork out a bit extra. But as our research shows, in many cases, you might be better off with a pie and a pint in the airport pub.”

Southend Skylife Lounge had the lowest score of all 20 lounges inspected, earning a score of just one out of five.

Aspire, owned by aviation services firm Swissport, said: “We take feedback on our services very seriously and are always looking for ways to improve our customers’ experience. We continually make changes to our menus, which are reviewed and enhanced on a seasonal basis. We are proud of the service and provision offered to our customers, who continue to rate us very well on peer recommendation review platforms.”

No 1, which admits children to its Edinburgh lounge, was not available for comment. Its website describes the lounge as having “a light and welcoming feel thanks to its triple-height atrium alongside the library and bistro areas”.